21256042163400 has 288 divisors, whose sum is σ = 77879538828000. Its totient is φ = 5152640486400.

The previous prime is 21256042163399. The next prime is 21256042163431. The reversal of 21256042163400 is 436124065212.

21256042163400 is a `hidden beast` number, since 2 + 1 + 2 + 5 + 604 + 2 + 1 + 6 + 3 + 40 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 436902276 + ... + 436950924.

It is an arithmetic number, because the mean of its divisors is an integer number (270415065375).

Almost surely, 2^{21256042163400} is an apocalyptic number.

21256042163400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21256042163400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38939769414000).

21256042163400 is an abundant number, since it is smaller than the sum of its proper divisors (56623496664600).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21256042163400 is a wasteful number, since it uses less digits than its factorization.

21256042163400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 70749 (or 70737 counting only the distinct ones).

The product of its (nonzero) digits is 69120, while the sum is 36.

The spelling of 21256042163400 in words is "twenty-one trillion, two hundred fifty-six billion, forty-two million, one hundred sixty-three thousand, four hundred".